1. Field of the Invention
The present invention relates to an organic electroluminescent display (OELD) device, more particularly, to an OELD device and a method of fabricating the OELD device using a shadow mask.
2. Discussion of the Related Art
Recently, a flat panel display device, such as a plasma display panel (PDP), a liquid crystal display (LCD) device and an OELD device, is developed and used instead of a cathode ray tube (CRT). Among these flat panel display device, since the OELD device, which is a self-luminance type, does not require a backlight unit as a light source, it is capable of being thin and light. Compared with the LCD device, the OELD device has a wide viewing angle, high contrast ratio and low power consumption. Moreover, the OELD device can be driven with low direct current voltages and has a fast response time. In addition, the OELD device has a strong durability to impacts and has low production costs.
Generally, in the OELD device, both array elements including a driving thin film transistor (TFT), and an organic luminescent diode are formed on a single substrate. Accordingly, production yield of the OELD device depends on production yield of the single substrate. Even if one of the array elements and the organic luminescent diode has defects, the OELD device is concluded to an inferior good. Accordingly, production yield of the OELD device decreases.
To this problem, a dual-panel type OELD device is suggested. In the dual-panel type, an array element and an organic luminescent diode are formed on different substrates from each other. Accordingly, production yield increases. In a process of fabricating an organic luminescent diode on a substrate, an organic luminescent layer is formed using a shadow mask having a stripe pattern.
FIG. 1 is a schematic plane view showing a shadow mask for fabricating a dual-panel type OELD device according to the related art. As shown in FIG. 1, the shadow mask SM includes a plurality of blocking portions 10 and a plurality of openings 20 between the plurality of blocking portions 10. An organic luminescent material is deposited on a substrate through the plurality of openings 20 to form an organic luminescent layer.
The above-mentioned shadow mask SM is fabricated through an etching process. Unfortunately, a blocking portion 10 at end sides of the shadow mask SM has undesired width due to an error in the etching process. Accordingly, the plurality of blocking portions 10 are divided into normal patterns S1 and dummy patterns S2. The dummy patterns S2 have an undesired width and are disposed at both end sides of the shadow mask SM. The normal patterns S1 have a desired width and are disposed between the dummy patterns S2. Accordingly, the normal pattern S1 are disposed to correspond to a pixel region, the dummy pattern S2 are disposed to corresponds to a dummy pixel region at a periphery of the pixel region, and thereby forming a desired organic luminescent layer in the pixel region. The more the shadow mask SM has the dummy patterns S2, the greater an uniformity of width of normal patterns S1. As a result, the more the shadow mask SM has the dummy patterns S2, the greater production yield is.
In an OELD device adopting a chip on glass (COG) type, there is a limitation for the dummy patterns. Namely, in the COG type, a power supply terminal of the array substrate contacts an electrode of an organic luminescent diode to apply a power to the organic luminescent diode. Since there is a narrow space, where the dummy pixel region is formed, due to the COG type, the shadow mask does not have sufficient dummy patterns such that a uniformity in the width of the normal pattern degraded. A displaying quality is deteriorated.